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https://issues.apache.org/jira/browse/THRIFT-2642?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16075348#comment-16075348
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Eric Conner edited comment on THRIFT-2642 at 7/5/17 8:27 PM:
-------------------------------------------------------------

Hi [~jensg],

Thanks for the follow up.  This pull request 
https://github.com/apache/thrift/pull/1293 is my attempt at a fix (which I 
linked above).  Can someone review it?

I also outlined the approach above.  Copied here:

I followed the fbthrift approach. At a high level, the change
Moves all thrift_spec definitions to the end of the ttypes file. Or, in the 
case of a service, after the service definition.
Changes the initial declaration of the spec for a TStruct to [<Struct>, None]
Uses a method call ``fix_spec`` to fill in the spec to [<Struct>, 
<Struct>.thrift_spec]
(Basically exactly what fbthrift does)

I should note that this does not solve the case of co-recursive structures, a 
problem that fbthrift also suffers from.  Co-recursive structs can be created 
but they cannot be serialized or deserialized (leads to infinite loop).


was (Author: econner724):
Hi [~jensg],

Thanks for the follow up.  This pull request 
https://github.com/apache/thrift/pull/1293 is my attempt at a fix (which I 
linked above).  Can someone review it?

I also outlined the approach above.  Copied here:

I followed the fbthrift approach. At a high level, the change
Moves all thrift_spec definitions to the end of the ttypes file. Or, in the 
case of a service, after the service definition.
Changes the initial declaration of the spec for a TStruct to [<Struct>, None]
Uses a method call ``fix_spec`` to fill in the spec to [<Struct>, 
<Struct>.thrift_spec]

I should note that this does not solve the case of co-recursive structures, a 
problem that fbthrift also suffers from.  Co-recursive structs can be created 
but they cannot be serialized or deserialized (leads to infinite loop).

> Recursive structs don't work in python
> --------------------------------------
>
>                 Key: THRIFT-2642
>                 URL: https://issues.apache.org/jira/browse/THRIFT-2642
>             Project: Thrift
>          Issue Type: Bug
>          Components: Python - Compiler, Python - Library
>    Affects Versions: 0.9.2
>            Reporter: Igor Kostenko
>
> Recursive structs in 0.9.2 work fine in c++ & c#, but not in python, because 
> generated code trying to use objects which not constructed yet.
> Struct:
> {code}
> struct Recursive {
> 1: list<Recursive> Children
> }
> {code}
> Python code:
> {code}
> class Recursive:
>   thrift_spec = (
>     None, # 0
>     (1, TType.LIST, 'Children', (TType.STRUCT,(Recursive, 
> Recursive.thrift_spec)), None, ), # 1
>   )
> {code}
> Error message:
> {code}
> Traceback (most recent call last):
>   File "ttypes.py", line 20, in <module>
>     class Recursive:
>   File "ttypes.py", line 28, in Recursive
>     (1, TType.LIST, 'Children', (TType.STRUCT,(Recursive, 
> Recursive.thrift_spec)), None, ), # 1
> NameError: name 'Recursive' is not defined
> {code}



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